I am currently building a Ruby-on-Rails based invoicing application (yes, yet another one!) that enables freelancers and small companies to write their invoices in an easy-to-use fashion. The application is multilingual and targeted at a range of different countries and markets.

Now one question I put to myself is: How common is it that a user will produce invoices in different currencies?

As it happens I am a freelancer as well and since the beginning of my career 7 years ago I have written all my 300 invoices in euro. There wasn't a single occasion on which I had to write an invoice in dollar or another currency. I can't even think of a use case that would require me to do that.

Maybe this is different where you live? Please let me know if you ever had to deviate from your local currency when invoicing a client. And even if not, would you look for such a feature in an online invoicing application (if you had to pick one)?